POC: jQuery modify single AJAX headers

HTML

<script type='text/javascript' src='http://code.jquery.com/jquery-1.7.1.min.js'></script>

JavaScript

/*global jQuery*/
jQuery(function () {
    $.ajax({
        url: "http://fiddle.jshell.net/",
        dataType: "html",
        "beforeSend": function(xhr) {
            // Works fine.
            xhr.setRequestHeader("X-Requested-With", {
                toString: function() {
                    return "";
                }
            });
            // Logs error on Chrome (probably others) as "Refused to set unsafe header "Referer".
            xhr.setRequestHeader("Referer", {
                toString: function() {
                    return "";
                }
            });
        }
    }).done(function (data) {
        $("<div>").text("ajax success").appendTo("body");
    });
});